If it's 5.6.x, then just use
KUAL and
MobileRead Package Installer to install everything you'll need installed.
Additionally install
Rescue Pack and
Coward's Rescue Pack (after RP). (So even if you'll have any software problems you'll recover from them easily enough)
To block all further updates just install and activate
BackDoorLock. (also you can create "update.bin.tmp.partial" folder when you simply connect it to via USB, but it's only additional precaution, and probably not needed anymore if you have BackDoorLock activated)
P.S. If you have problems finding any package, it almost always can be found on
Snapshots of NiLuJe's hacks or on a
List of KUAL Extensions.